Chapter 28: Hard or Sharp Objects
Updated:
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Potential Food Safety Hazard
o Ferrous metal objects
o Nonferrous metal objects
o Nonmetallic objects
o Metal inclusion
o Glass Inclusion
Control Measures
o Metal inclusion
o Glass Inclusion
o Nonmetallic objects
FDA Guidelines
o Hard or sharp objects
o Metal inclusion
o Glass Inclusion
Critical Aspects of Processes
o Metal inclusion
Analytical Procedures
o Rapid determination of glass in particle-free food products (HC)
o Other analytical procedures
References, Including General Physical Hazard References
Author: Alan R. Olsen, U.S. Food and Drug Administration
Updated by Bob Price, University of California, Davis
Potential Food Safety Hazard
Top
Foreign objects in foods are considered adulteration. Foreign objects can be broadly classified as
1) food safety hazards (e.g., glass) and 2) food nonsafety hazards (e.g., filth). Foreign objects that
are physical hazards are referred to as hard or sharp objects. Hard or sharp objects are divided
into metallic objects (Tables 28-1 and 28-2) and non-metallic objects (Table 28-3). Metallic
objects are further divided into ferrous metals (Table 28-1) and non-ferrous metals (Table 28-2).
Hard or sharp foreign objects in food may cause traumatic injury including laceration and
perforation of tissues of the mouth, tongue, throat, stomach and intestine as well as damage to
the teeth and gums. From 1972 through 1997, the FDA Health Hazard Evaluation Board
evaluated approximately 190 cases of hard or sharp foreign objects in food. These include cases
of both injury and non-injury reported to FDA. The Board found that foreign objects that are less
than 7 mm, maximum dimension, rarely cause trauma or serious injury except in special risk
groups such as infants, surgery patients, and the elderly. The scientific and clinical literature
supports this conclusion.
Hard or sharp natural components of a food (e.g. bones in seafood, shell in nut products) are
unlikely to cause injury because of awareness on the part of the consumer that the component is
a natural and intrinsic component of a particular product. The exception occurs when the food's
label represents that the hard or sharp component has been removed from the food, e.g., pitted
olives. The presence of the naturally occurring hard or sharp object in those situations (e.g., pit
fragments in pitted olives) is unexpected and may cause injury. FDA has established Defect
Action Levels for many of these types of unavoidable defects in other Compliance Policy Guides
and therefore they are not subject to the guidance in this document (FDA, 1999).
The following tables list examples of the types of hard or sharp objects that pose a potential
physical hazard.
Table 28-1. Ferrous metal objects
Ferrous Metal Potential
Objects
Hazard
Possible Source(s)
Hook
Trauma
Raw materials (fish hook)
Wire
Trauma
Raw materials (e.g., twist
tie)
Top
Processing (e.g.,
screen/sieve)
Sliver
Trauma
Processing (e.g., container
strap)
Staple
Trauma
Personal effects
Thumb tack
Trauma
Personal effects
Nail
Trauma
Maintenance
Key
Dental
Personal effects
Hand tool
Dental
Maintenance
Machinery part Dental
Processing
Table 28-2. Nonferrous metal objects
Nonferrous
Potential
Metal Objects Hazard
Possible Source(s)
Shaving
Trauma
Maintenance (e.g., plumbing
repair)
Wire
Trauma
Maintenance (e.g., electrical
wire offcut)
Processing (e.g.,
screen/sieve)
Sliver
Trauma
Processing
Jewelry
Trauma/
Dental
Personal Effects
Top
Button
Dental
Personal effects
Stainless steel
Dental
Processing
Coin
Dental
Personal effects
Machinery part Dental
Processing
Loose solder/
welding slag
Dental*
Maintenance
Lead
weights/shot
Dental*
Raw materials
*May also pose a potential chemical hazard
Table 28-3. Nonmetallic objects
Nonmetallic
Objects
Potential
Hazard
Bone (sliver/chip)
Trauma
Processing (e.g., hard/sharp bone
pieces separated from flesh)
Wood splinter
Trauma
Raw materials (e.g., crate)
Top
Possible Source(s)
Processing (e.g., table, tool
handle)
Glass
Trauma
Processing (e.g., light fixture, jar)
Puncture vine
Trauma
Raw materials
Hard plastic
Trauma
Processing (e.g., tote bin,
packaging)
Personal effects (e.g., false
fingernail)
Insulation
Trauma
Maintenance (e.g., asbestos fiber)
Insect
Trauma
Raw materials (e.g., sharp spine)
Processing (e.g., dermestid setae)
Hard shell
Trauma/Dental Raw materials (Crustaceans)
Burr
Trauma/ dental Raw materials
Thorn
Trauma/ dental Raw materials
Button
Dental
Personal effects
Stone
Dental
Raw materials
Metal Inclusion
Metal fragments can cause injury to the consumer.
Top
Metal-to-metal contact, especially in mechanical cutting or blending operations, other equipment
with metal parts that can break loose, such as moving wire mesh belts, injection needles, screens,
portion control equipment, metal ties and can openers are likely sources of metal that may enter
food during processing.
FDA's Health Hazard Evaluation Board has supported regulatory action against product with
metal fragments of 0.3" (7 mm) to 1.0" (25mm) in length. See FDA Compliance Policy Guide
#555.425 (FDA, 2001a).
Glass Inclusion
Top
Glass fragments can cause injury to the consumer. FDA's Health Hazard Evaluation Board has
supported regulatory action against products with glass fragments of 0.3" (7 mm) to 1.0" (25
mm) in length. See FDA Compliance Policy Guide #555.425.
Glass inclusion can occur whenever processing involves the use of glass containers. Normal
handling and packaging methods, especially mechanized methods, can result in breakage. Most
products packed in glass containers are intended as a ready-to-eat commodity.
Glass fragments originating from other sources must be addressed where applicable in a
prerequisite sanitation program. The Seafood HACCP Regulation requires such a program
(FDA, 2001b).
Control Measures
Top
Metal Inclusion
Top
Control measures for "metal inclusion" can include:
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Periodically checking cutting or blending equipment or wire-mesh belts for damage or
missing parts;
Passing the product through metal detection or separation equipment.
Visually inspecting equipment for damage or missing parts may only be feasible with relatively
simple equipment, such as band saws, small orbital blenders, and wire-mesh belts. Other, more
complex, equipment may contain to many parts, some of which may not be readily visible, to
make such visual inspection reliable in a reasonable time period (FDA, 2001a).
Glass Inclusion
Control measures for "glass inclusion" can include:
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Visual examination of empty glass containers;
Cleaning (water or compressed air) and inverting empty glass containers;
Periodically monitoring processing lines for evidence of glass breakage;
Proper adjustment of capping equipment (not a complete control);
Top
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Visual examination of glass containers containing transparent liquid fishery products;
Passing the product through x-ray equipment or other defect rejection system (FDA,
2001b).
Nonmetallic objects
Top
Control measures for nonmetallic objects can include:
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Passing the product through an X-ray detector.
FDA Guidelines
Top
Hard or sharp objects
Top
Foods are considered adulterated if:
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The product contains a hard or sharp foreign object that measures 7 mm to 25 mm, in
length, and
The product is ready-to-eat, or according to instructions or other guidance or
requirements, it requires only minimal preparation steps, e.g., heating, that would not
eliminate, invalidate, or neutralize the hazard prior to consumption (FDA, 1999).
Metal Inclusion
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No metal fragments in finished product. (Note: FDA's Health Hazard Evaluation Board
has supported regulatory action against product with metal fragments of 0.3" [7 mm] to
1.0" [25mm] in length. See also FDA Compliance Policy Guide #555.425.), or
No broken or missing metal parts from equipment at the CCPs for "metal inclusion"
(FDA, 2001a).
Glass Inclusion
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Top
Top
No glass fragments in finished product. (Note: FDA's Health Hazard Evaluation Board
has supported regulatory action against products with glass fragments of 0.3" [7 mm] to
1.0" [25 mm] in length. See also FDA Compliance Policy Guide #555.425.)
No broken glass at the CCPs for "glass inclusion" (FDA, 2001b).
Critical Aspects of Processes
Top
Metal Inclusion
Top
Critical aspects of processes may include:
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The presence of metal fragments in product passing the CCP.
The presence of broken or missing metal parts from processing equipment (FDA, 2001a).
Analytical Procedures
Top
Rapid determination of glass in particle-free food products (HC ExFLP-7)
Top
Other analytical procedures
Top
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Bones and scales in grated tuna (Freeman, 1978)
Glass contamination of food (Gecan et al., 1990)
Glass in meat scraps (AOAC, 1995a)
Filth in shrimp (Olsen, 1988)
Shell in clams and oysters (AOAC, 1995b)
Shell in crabmeat (AOAC 1995c)
References, Including General Physical Hazard
References
Top
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